The present invention relates to a network interface apparatus for use in connecting between a general-purpose multimedia network carrying multimedia information of various types and a music network dedicated to electronic musical instruments, the dedicated network carrying information for controlling electronic musical instruments.
Conventionally, in the field of electronic musical instruments, a plurality of devices such as a keyboard, a tone generator, a sequencer and a mixer can be interconnected to constitute a music network system for performing data communication among these devices. Such a system can present automatic performance, ensemble performance and live performance, and can make composition, arrangement and recording of music. For a standard for carrying out data communication among the plurality of devices, MIDI is available in the field of electronic musical instruments. The devices complying with the MIDI standard are generally referred to as MIDI devices, which are in widespread use.
However, a communication protocol based on the MIDI standard has a relatively slow data transmission speed or bit rate. Especially, when many devices are interconnected to each other, such a MIDI protocol is inadequate for effectively operating the above-mentioned system in its entirety. The MIDI standard limits the transmission speed to 31.25 Kbits/sec. One of the reasons of this limitation is that some devices are limited in data transfer rate which is an amount of information that can be transferred in a unit time, due to poor internal processing ability or design limitation of these devices. Other devices, however, are fully compatible with fast transmission speeds higher than 31.25 Kbits/sec. Therefore, the current MIDI standard prevents these fast devices from providing full capabilities inherent thereto.
An advanced network system constitutes a LAN involving electronic musical instruments and other electronic equipments such as audio and video devices, instead of being constituted by electronic musical instruments alone. Since the current MIDI standard supports only unidirectional communication, it is difficult with the MIDI standard to network electronic equipments of bi-directional communication types together with electronic musical instruments of unidirectional communication type. This problem may be overcome by constituting a network system based on bi-directional communication protocol.
However, construction of a network with a protocol not supported by the MIDI standard presents another problem of making no more use of software resources such as programs and performance data developed in compliance with the MIDI standard and hardware resources such as MIDI devices and peripheral units.